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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-03-25 17:23:44 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:38:23 -0700 |
| commit | dad81a2026841b5e2651aab58a7398c13cc05847 (patch) | |
| tree | f666432234764e97893d37155429223e2c44bd8c /init | |
| parent | 32071141b2448458479932fe726ce892cbe1b4e4 (diff) | |
| download | lwn-dad81a2026841b5e2651aab58a7398c13cc05847.tar.gz lwn-dad81a2026841b5e2651aab58a7398c13cc05847.zip | |
srcu: Introduce CLASSIC_SRCU Kconfig option
The TREE_SRCU rewrite is large and a bit on the non-simple side, so
this commit helps reduce risk by allowing the old v4.11 SRCU algorithm
to be selected using a new CLASSIC_SRCU Kconfig option that depends
on RCU_EXPERT. The default is to use the new TREE_SRCU and TINY_SRCU
algorithms, in order to help get these the testing that they need.
However, if your users do not require the update-side scalability that
is to be provided by TREE_SRCU, select RCU_EXPERT and then CLASSIC_SRCU
to revert back to the old classic SRCU algorithm.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig index d269f2ca17b8..558cc3638ab9 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -526,15 +526,32 @@ config SRCU permits arbitrary sleeping or blocking within RCU read-side critical sections. +config CLASSIC_SRCU + bool "Use v4.11 classic SRCU implementation" + default n + depends on RCU_EXPERT && SRCU + help + This option selects the traditional well-tested classic SRCU + implementation from v4.11, as might be desired for enterprise + Linux distributions. Without this option, the shiny new + Tiny SRCU and Tree SRCU implementations are used instead. + At some point, it is hoped that Tiny SRCU and Tree SRCU + will accumulate enough test time and confidence to allow + Classic SRCU to be dropped entirely. + + Say Y if you need a rock-solid SRCU. + + Say N if you would like help test Tree SRCU. + config TINY_SRCU bool - default y if TINY_RCU + default y if TINY_RCU && !CLASSIC_SRCU help This option selects the single-CPU non-preemptible version of SRCU. config TREE_SRCU bool - default y if !TINY_RCU + default y if !TINY_RCU && !CLASSIC_SRCU help This option selects the full-fledged version of SRCU. |